Hi, I hope I understand you correctly,
Record your motion path on the main timeline for the element using the red record button
When done, put the timeline back to the start position.
Create your timeline two.
With the element in the original start position that it would be in the main timeline and the timeline at 0 seconds start position. Click the red record button to start the Motion path recording.
Now drag the element to where you want it to start from in this second timeline.
This will place a Motion path keyframe right at the start which will hold the new start position.
Now move the play head to 1 second ( for example) and drag the element to it's next position.
This will place another Motion path keyframe at the 1 second mark and join the two sets of Motion path keyframes together.
Stop the recoding.
In my example I use a button to start timeline two in preview
Thats it, if I understand you correctly.